all: new feature: added a Brazilian Portuguese translation of the programs by Thiago Kühn (see AUTHORS).

mkvpropedit, mmg’s header editor: bug fix: fixed a failed assertion in libEBML when writing the same changes twice to certain files (those for which a seek head with a single entry pointing to the elements modified by mkvpropedit/mmg’s header editor; e.g. x264 creates such files). Fixes #1007.